OK, Kevin poses SQL questions (good ones)

This ex-English teacher has decided to pose some culture questions to the many erudite members here.
The opening query is fairly simple.
A couple of rules:
- no web searching for answers.
- close only counts in horseshoes.
- I won't be grading on a curve.

OK- for this line:

A Book of Verses underneath the Bough

What is the EXACT spelling of the name of the complete poem?
What is the EXACT spelling of the name of the author?
Who translated the poem from its original Persian? (hint - no relation)
What verse in the complete poem refers to digits and, in modern parlance, prohibits the use of the backspace key?

This one for extra credit:
What is the significance of the name of the complete poem?
If you get that one, I'll really be impressed.